1. Field of the Invention
The present invention relates to preparation of mixtures rich in 3-chloro-2-trichloromethyl pyridine by non-catalytic liquid phase chlorination of alpha-picoline hydrochloride. 3-chloro-2-trichloromethyl pyridine is useful, for example, as an intermediate in the preparation of various herbicidal compositions as described in Johnston et al U.S. Pat. No. 3,317,549.
2. Description of the Prior Art
Known processes for preparation of 3-chloro-2-trichloromethyl pyridine are described in Brett et al U.S. Pat. No. 2,679,453 and Johnson et al U.S. Pat. No. 3,317,549 (at page 12, lines 29-36). In the process disclosed in U.S. Pat. No. 2,679,453, alpha-picoline is chlorinated on a batch basis at a temperature from 50.degree. C. to 150.degree. C. in the presence of water to yield various chlorinated pyridine/picoline compositions. Taplin U.S. Pat. No. 3,424,754 describes the chlorination of alpha-picoline hydrochloride in the temperature range of from 140.degree. C. to 230.degree. C. to yield 6-chloro-2-trichloromethyl pyridine and compositions enriched in said compound, without any indication as to formation of any 3-chloro-2-trichloromethyl pyridine by the process. William James Sell in an article appearing at J. Chem. Soc. Vol. 87, pp 799 et seq. (1905) discloses a process of preparing alpha-picoline hydrochloride by direct addition of anhydrous hydrogen chloride gas to alpha-picoline, and the chlorination of alpha-picoline hydrochloride at temperatures of about 105.degree. C.-110.degree. C.